19 Jan
2011
19 Jan
'11
4:35 a.m.
On 01/19/2011 03:39 AM, gene heskett wrote:
On Tuesday, January 18, 2011 09:16:00 pm Robin Gareus
did opine:
nope. I mean tubes like pipes in the wall or floor that allow one to
easily replace cables that run inside those tubes. It'd still be a major
re-wiring task but at least one can change the wires easily compared to
in-wall mounted cables.
Some trivial mechanical suggestion for a future-proof studio (not an
electrical one) at least if future > 10 years and esp. if you don't want
to rip the whole studio apart for major renovation.
but wave-guides are a good drift.
Hi Joern,
If it is an option: use Leerrohre (DE for "empty tubes" ?) to make it
future-proof, rather than to rely on cable-standards. In a few years you
may want to replace coax with optical or whatever.
I think that would translate to wave-guides in English but check your
sizes, at 3Ghz, they are hundreds of times greater cross sectional area
than a coax would be. Also, a lot less loss if properly terminated. 250
feet of it has less loss than 3 feet of this mini-coax in common use now,
but you would have at least $20k in that 250 feet too.
In short, optical seems the best way to go. I helped setup a fiber link
several years ago that was 39 kilometers long, and the end to end optical
loss was 0.5 db. You can't do that with wave-guide or a G-Line, and coax
would have likely been 60-80db of loss and much less bandwidth, we stuffed
4 television channels though that fiber.
sure, one question is if it can be done by Joern and another is if
shelling out more euros for a proper crimp-on connectors is worth not to
worry about possible bad solder joints.
The only question I can answer is #4: The problem
is reflections caused
by skin-effect if you do solder them. Back in the days that I spent in
the physics dept. we used solder-less crimp connectors for everything
high-freq.
I can't testify about 3Gb+ solder joints, but I do know that properly done,
they are invisible at .6 Ghz. You may have to putz with it a bit, but it
CAN be done. And, I have yet to see a physics prof that actually
knew which end of the
iron got hot, let alone could actually make a good joint. Too many have
the attitude that their hands do not fit the tools and make no effort to
teach themselves how to do it.
LOL.
This was/is experimental physics in cooperation with
hardware-informatics. Eventually we designed custom ASICs and did the
PCBs and soldering of the prototypes ourself, pretty much everything is
non-standard since it must be able to work in a >5 Tesla magnetic field.
It is currently running inside the ALICE detector @LHC.
I will allow the comment that when fabricating
wave-guide parts and filters
for 7Ghz work, which I have done a few of decades ago, those were usually
silver soldered because the regular tin/lead solders surfaces oxidized with
time much worse, screwing with the skin effect losses. Silver oxide may
look fugly, but is still a pretty fair conductor when frequencies are in
the realm where skin effect reigns supreme. Just as true inside the wave-
guide as it is on the skin of a coax conductor.
interesting. I do remember a drawer with at least 15 different kind of
solder. Now I know what that silver stuff in there was in there for :)
Cheers!
robin